A socket is commonly referred to as the portion of a prosthesis that fits around and envelopes a residual limb or stump, and to which prosthetic components, such as a foot, are attached. When providing a socket to an amputee, it is essential to properly fit the socket and align various parts of the prosthesis to the amputee. Fitting and alignment of the socket are difficult tasks to perform, and require extensive knowledge, training and skill on behalf of the prosthetist.
Typically, sockets for definitive prostheses are customized for a residual limb of a particular wearer. According to one method, the sockets are formed over a model of the stump, such as one formed by plaster-of-paris, in a manner that is used to distribute forces between the socket and the stump in a comfortable way to the amputee. In another method, the socket may be obtained from computer aided design by modeling the shape of the stump, and subsequently forming a model. Once the model is obtained in either of these methods, a socket is formed over the model by using fabric and liquid plastic resin to obtain a definitive rigid socket customized to a particular limb.
Proper fitting of a socket to the stump is critical to the success of the prosthesis. The socket must fit closely to the stump to provide a firm connection and support, but must also be sufficiently loose to allow for circulation. In combination with proper fitting, the socket must transfer loads from the residual limb to the ground in a comfortable manner.
Most prosthetic sockets are permanently formed to a customized shape that is static, meaning that the socket does not account for shape and volume fluctuations of the residual limb. When there are shape and volume fluctuations, the fitting of the socket is impeded, with these sockets causing discomfort, pain and soft tissue breakdown of the stump. In addition, conventional sockets tend to be bulky and cumbersome to wear, and may be difficult to don making the residual limb uncomfortable when worn.
It is desirable to provide a simplified and compact prosthesis system that overcomes the drawbacks over known prosthesis systems. Particularly, it is advantageous to provide a socket system that is off-the-shelf and capable of accommodating a variety of residual limb sizes. It is also desired that a socket system be adjustable to allow for volume and shape fluctuations, and in effect, provide a dynamic socket as opposed to the known static sockets. The adjustable socket can better adjust for pressure distribution, and maintain comfort to the amputee over a range of care and residual limb conditions.